I keep looking for something like a mechanical version of the MS Sculpt keyboard. I like that the sides are solidly attached, the slight tenting, and that there's a bit of a profile to the keys--they're not just planar. Too many of the ergonomic split keyboards are infinitely adjustable, but the adjustments are finicky.
There's the Cloud Nine C989 [1] (though I don't know how the mechanism to keep the two halves attached works), or for a DIY option there's the NEK Type A [2].
For the profile of the keys themselves, you can make small changes to an existing keyboard by changing the keycaps -- although it's not always easy to find all the sizes required for an unusual keyboard. See [3]. I have SA keycaps on an otherwise-flat keyboard.
